Sensing and control arrangements for respiratory device

ABSTRACT

Various characteristics of a gas flow can be sensed at the end of a respiratory conduit near the patient interface using a sensing module. The sensing module can be removable from the patient end of the respiratory conduit for ease of use and ease of cleaning. The sensor module can transmit sensor data over the same wires used to heat the respiratory conduit.

INCORPORATION BY REFERENCE TO ANY PRIORITY APPLICATIONS

Any and all applications for which a foreign or domestic priority claimis identified in the Application Data Sheet as filed with the presentapplication are hereby incorporated by reference under 37 CFR 1.57.

BACKGROUND

1. Technical Field

The present disclosure generally relates to sensor modules and controlsystems for use with gas therapy devices.

2. Description of the Related Art

In patients suffering from obstructive sleep apnea (OSA), muscles thatnormally keep the upper airway open relax during slumber to the extentthat the airway is constrained or completely closed off, a phenomenonoften manifesting itself in the form of snoring. When this occurs for aperiod of time, the patient's brain typically recognizes the threat ofhypoxia and partially wakes the patient in order to open the airway sothat normal breathing may resume. The patient may be unaware of thesewaking episodes, which may occur as many as several hundred times persession of sleep. This partial awakening may significantly reduce thequality of the patient's sleep, over time potentially leading to avariety of symptoms, including excessive daytime sleepiness, chronicfatigue, elevated heart rate, elevated blood pressure, weight gain,headaches, irritability, depression and anxiety.

Obstructive sleep apnea is commonly treated with the application ofpositive airway pressure (PAP) therapy. PAP therapy involves deliveringa flow of gas to a patient at a therapeutic pressure above atmosphericpressure that will reduce the frequency and/or duration of apneas,hypopneas, and/or flow limitations. The therapy is often implemented byusing a PAP device to deliver a pressurized stream of gases through aconduit to a patient through a patient interface or mask positioned onthe face of the patient. A humidifier can be positioned in-line betweenthe PAP device and the patient interface to heat and humidify the gases.

SUMMARY

Sensors can be used to determine characteristics of gases used in arespiratory therapy system. The determined gas characteristics can beused in the control of various components of the respiratory therapysystem. For example, if the gases temperature desired at the end of agas conduit is 37° C., if the temperature of the gases at or near theend of the conduit can be measured, then the heat output of a conduitheater can be adjusted according to a function of the desired gasestemperature and the measured gases temperature to help ensure that thedesired gases temperature is achieved. It is desirable to measure gascharacteristics of gases as close to a patient using the respiratorytherapy system as possible to improve the accuracy of models adapted tocontrol the respiratory therapy system components or to facilitate theuse of closed-loop control systems. Transmitting signals from sensorspositioned relatively close to the patient to a signal receiver located,for example, at a flow generator upstream of the sensors can require theuse of additional wires for data transmission, which can decrease theconvenience or increase the cost of using the sensors. If usage of thesensors is not desired, their presence can unnecessarily increase thecost of the respiratory therapy system. Solutions are sought for one ormore of the above concerns.

Certain features, aspects and advantages of at least one of theconfigurations disclosed herein include the realization that a sensormodule may be positioned between components of a respiratory therapysystem. For example, the sensor module can be positioned between a gasesconduit and a patient interface. The sensor module can comprise a gasesinlet, a gases outlet, and a lumen extending between the gases inlet andthe gases outlet. The sensor module can also comprise one or moresensors adapted to measure or determine one or more characteristics ofgases passing through the lumen. Data signals obtained from the sensorscan be transmitted over, for example, wires used to heat the gasesconduit and/or energize the sensor module by superimposing the datasignals over power signals transmitted over the wires. The sensor modulecan releasably engage with the components of the respiratory therapysystem, allowing for a modular or convenient design. Additionally,because the sensor module is not permanently joined to the gasesconduit, the sensor module can be reused.

DESCRIPTION OF THE DRAWINGS

Specific embodiments and modifications thereof will become apparent tothose skilled in the art from the detailed description herein havingreference to the figures that follow, of which:

FIG. 1 shows a schematic diagram of a respiratory therapy system.

FIGS. 2A-2C show various perspective views of a sensing system andcomponents thereof.

FIG. 3 shows an exploded view of a sensor module.

FIG. 4 shows a circuit diagram.

FIGS. 5A-5B show control algorithms for a respiratory therapy system.

FIGS. 6A-6C show various perspective views of a sensing system andcomponents thereof.

FIGS. 7A-7I show various perspective views of a sensing system andcomponents thereof.

DETAILED DESCRIPTION

With reference to the non-limiting exemplary embodiment illustrated inFIG. 1, a respiratory therapy system 100 is shown. The respiratorytherapy system 100 comprises a flow generator 102. The flow generator102 comprises a positive airway pressure or PAP device. The flowgenerator 102 receives gases from a gases inlet 104 and propels them toa humidifier 106. The flow generator 102 and humidifier 106 may be partof an integrated flow delivery system or may share a housing 108. Thehumidifier 106 heats and humidifies the gases. The humidifier 106comprises a quantity of water or another moisturizing agent 107(hereinafter referred to as water). The humidifier 106 also comprises aheating plate 109 that may be used to heat the water in the humidifier106 to encourage water vaporization and/or entrainment in the gas flowand increase the temperature of gases passing through the humidifier106. The heating plate may, for example, comprise a resistive metallicheating plate. Heated and humidified gases are passed from a humidifieroutlet to a gases conduit 112. The gases conduit 112 comprises a heatingwire 114. The heating wire 114 reduces or prevents the condensation ofmoisture along the walls of the gases conduit 112. The heating wire 114is positioned in, on, around or near the gases conduit 112. Gases arepassed from the gases conduit 112 to a patient interface 116 throughwhich they are delivered to a patient. The respiratory therapy system100 comprises a controller 111 that controls the operation of the flowgenerator 102. The controller 111 also controls the operation of thehumidifier 106. The respiratory therapy system 100 comprises aninput/output (I/O) module 110. The I/O module 110 comprises a way for auser to interact with and set parameters for the flow generator 102and/or humidifier 106 (including but not limited to target gaseshumidity levels, target gases temperature levels and target gasespressure levels) as well as receive information regarding the operationof the respiratory therapy system 100 and/or its components. The I/Omodule 110 may comprise, for example, buttons, knobs, dials, switches,levers, touch screens, speakers, displays and/or other input or outputelements. In some configurations, the humidifier 106 may not be present.In some configurations, the flow generator 102 may comprise elementsother than PAP devices, including but not limited to high flow therapydevices or ventilation devices. In some configurations, the patientinterface 116 may comprise a sealing, semi-sealing or non-sealinginterface. For example, the patient interface 116 may comprise an oralmask, an oro-nasal mask, a full face mask, a nasal pillows mask, anendotracheal tube, a combination of the above, or some other gasconveying system or apparatus.

As seen in FIG. 1, the respiratory therapy system 100 includes a sensormodule 300, 600, 700. The sensor module 300, 600, 700 is configured tobe removably attached to the gases conduit 112 and to the patientinterface 116. The sensor module 300, 600, 700 comprises one or moresensors adapted to determine one or more characteristics of gasespassing through or along the sensor module 300, 600, 700. The sensorscan include, for example, one or more of a relative humidity sensor, anabsolute humidity sensor, a temperature sensor, a dew point sensor, anenthalpy sensor, a pressure sensor, a flow rate sensor, an oxygensensor, a CO₂ sensor, or a nitrogen sensor, but can include one or moreother sensors. In some configurations, the sensor module 300, 600, 700can comprise one or more sensors adapted to determine one or morecharacteristics of a patient using the respiratory therapy system 100 orof the ambient environment outside of the respiratory therapy system100. The sensors can include, for example, one or more of an acousticsensor or microphone, a light sensor or camera, an ambient temperaturesensor, an ambient humidity sensor, or an accelerometer, but can includeone or more other sensors. In other configurations, the sensor module300, 600, 700 can be positioned between, at or near other components ofthe respiratory therapy system 100. For example, the sensor module 300,600, 700 can be positioned between the flow generator 102 and thehumidifier 106, or between the humidifier 106 and the conduit 112. Thesensor module 300, 600, 700 is further described in the followingdisclosure with reference to the accompanying figures.

Some possible utilities for some such sensors present in the sensormodule 300, 600, 700 are disclosed below.

Pressure and/or flow sensors may be used within the sensor module 300,600, 700 to obtain a measure of flow data, flow waveforms, pressure dataand/or pressure waveforms proximal to the patient. The data or waveformscan be used, for example, to feed information into algorithms adapted tofacilitate apnea or hypopnea detection, pressure/flow control,expiratory pressure relief, and/or automatic pressure control/titrationalgorithms.

Enthalpy sensors may be used within the sensor module 300, 600, 700 toobtain a measure of the heat energy of gases present proximal to thepatient. Measured enthalpy values may be used to calculate the level ofheat energy and/or humidity delivered to the patient.

Light sensors may be used to monitor the light level of the environmentaround the sensor module 300, 600, 700. For example, if the light levelof the environment is lower than a threshold light level, the patientmay have turned off the lights in a room in preparation to sleep. Thesensor module 300, 600, 700 may then send a signal to the controller 111to initiate therapy.

Acoustic sensors/microphones may be used to monitor the level of noisein the respiratory therapy system 100 and/or in the environment outsideof the respiratory therapy system 100. They may be used to, for example,detect patient snoring or other noises that indicate the presence of anapnea or hypopnea event. The sensor module 300, 600, 700 may transmitsome such sensor signals to the controller 111, which may in turn usesuch data to control, for example, the flow generator 102 to modulatethe level of pressure of gases delivered. If the sound level of theenvironment is less than a threshold, the patient may be preparing tosleep, and so a signal may be communicated to the controller 111 toinitiate therapy. In some configurations, an acoustic sensor may be usedto aid in the diagnosis of fault conditions of, for example, a motor ofthe flow generator 102.

CO₂ and O₂ sensors, if supplemental oxygen and/or carbon dioxide arebeing delivered using the respiratory therapy system 100, may be used tohelp determine the efficacy of the oxygen or carbon dioxide deliverytherapy. In some configurations, the sensors may be used to determinethe efficacy of, for example, a bias flow or venting mechanism used inor on the patient interface 116 or elsewhere in the respiratory therapysystem 100.

Accelerometer/gyroscopic sensors may be used to determine theorientation of the user during slumber, particularly when the sensormodule 300, 600, 700 is secured to the patient interface 116.Information regarding the orientation may be used to modulate thepressure of delivered gases (through, for example, adjustment of theoperation parameters of the flow generator 102) to treat the patientand/or improve the comfort of therapy. For example, if the patient is ina prone position, the risk of hypopnea and/or apnea events may be lessthan if the patient is supine. In some configurations, then, thepressure of gases delivered may be decreased if the accelerometerdetermines that the patient is positioned in the prone position.

FIGS. 2A-2C show a non-limiting first exemplary configuration for asensing system incorporating a sensor module 300. As shown, the gasesconduit 112 (comprising heater wire 114 and gases passageway or lumen113) comprises a cuff 118. The cuff 118 is overmoulded with an overmouldstructure 202. The overmould structure 202 may comprise, for example, anovermoulded layer of silicone. The overmould structure 202 comprises alumen 203 in pneumatic communication with the lumen 113 and an outlet204. The outlet 204 may pneumatically interface with, for example, thepatient interface 116 described elsewhere in this disclosure withreference to FIG. 1. The overmould structure 202 additionally comprisesa region 207 adapted to accommodate the sensor module 300. The region207 comprises a ridged and raised section 208. The ridged and raisedsection 208 comprises an aperture 210. The ridged and raised section 208defines a recessed area 206 in which the sensor module 300 is held. Thesensor module 300 comprises a side protrusion 306 adapted to fit throughthe aperture 210 (through, for example, a snap fit mechanism) to helpretain the sensor module 300 in the recessed area 206. The sideprotrusion 306 can be beveled or substantially arcuate in such a waythat promotes both easy retainment and release of the sensor module 300from the recessed area 206 and aperture 210. The sensor module 300 canalso comprise a tab 304. The tab 304 can be pressed by a patient or userto facilitate the extraction of the sensor module 300 from the recessedarea 206. The sensor module 300 comprises an insignia or symbol 302 thatcan inform the patient or user as to the capabilities of the sensormodule. For example, a teardrop symbol 302 as shown in FIGS. 2A and 2Cmight imply that the sensor module 300 is capable of humidity sensing.In other configurations, the sensor module 300 might have no insignia orsymbol 300. In other configurations, the sensor module 300 can interfacewith the overmould structure 202 and/or conduit 112 via other means,including but not limited to latch/catch arrangements and adhesives.

FIG. 2B shows that the recessed area 206 comprises an electricalinterface 214. The electrical interface 214 comprises a pair ofelectrical terminals that interface with corresponding or complementaryelectrical terminals on the sensor module 300. The electrical interface214 permits electrical communication between the sensor module 300 andthe heating wire 114, and in turn the heating wire 114 is electricallylinked to the controller 111. Through the electrical interface 214, thesensor module 300 can transmit a data signal to a controller locatedupstream from the sensor module 300. For example, the data signal can betransmitted to the controller 111 adapted to control the flow generator102 and/or humidifier 106 as described elsewhere in this disclosure withreference to FIG. 1. The data signal may be overlaid or superimposedover a power signal that passes through the heating wire 114 to providepower to the sensor module 300 and/or provide resistive heating to theheating wire 114. In other configurations, the data signal may betransmitted to components of the respiratory therapy system 100wirelessly, e.g. using RFID or wireless communications technologiesincluding but not limited to Wi-Fi, Bluetooth, 2G, 3G, or 4G. Furtherattention is given to the details of data transfer elsewhere in thisdisclosure with reference to the accompanying figures.

The recessed area 206 additionally comprises a gases sampling aperture212. The gases sampling aperture 212 at least in part defines a gasessampling passageway extending between the lumen 203 and one or moresensors positioned within the sensor module 300. The gases samplingaperture 212 in use seals against the sensing module 300. In someconfigurations, a section of the recessed area 206 defining the gasessampling aperture 212 may be adapted to seal against the sensing module300. In other configurations, a section of the recessed area 206defining the gases sampling aperture 212 and/or a section of the sensormodule 300 defining a complementary aperture of the sensor module 300 atleast in part defining the gases sampling passageway may comprise asealing structure configured to promote pneumatic sealing between therecessed area 206 and the sensor module 300.

FIG. 3 demonstrates an exploded view of the sensor module 300 shown inFIGS. 2A and 2C. The sensor module 300 comprises a module base 300D, amodule seal 300C, a printed circuit board (PCB) 300B, and a module cover300A. The module base 300D is adapted to support the sensor module 300.The module base 300D comprises a base aperture 312 in pneumaticcommunication with the gases sampling aperture 212 present on therecessed area 206. Gases entering the sensor module 300 through the baseaperture 312 are channeled through a seal aperture 314 of the moduleseal 300C. The module seal 300C can be produced from silicone or anothermaterial adapted to promote a sealed gas passageway between the sensormodule 300 and the recessed area 206 of the overmould structure 202.Gases passing through the seal aperture 314 contact one or more sensors316 positioned on the bottom of the PCB 300B. The PCB 300B comprises amicrocontroller 320 adapted to receive data signals from the one or moresensors 316 and transmit the data signals over the heating wire 114 (ata heating wire termination portion contacting the PCB 300B through therecess 308 present in the module base 300A, not shown) (using, forexample, a power signal modulator). The module cover 300A protects thePCB 300B and the gases sampling passageway in the sensor module 300. Themodule cover 300A interfaces with the module base 300D via a catch/latchmechanical fastener arrangement through the use of latches 310 presenton the exterior of the module base 300D and complementary catches (notshown) present in the inside of the module cover 300A. In someconfigurations, the module base 300D may comprise a single latch 310 andthe module cover 300A may comprise a single catch. In someconfigurations, the module base 300D may comprise catches and the modulecover may comprise complementary latches. In some configurations, themodule base 300D and the module cover 300A may be joined to one otherusing some other means, including but not limited to ultrasonic welding,radiofrequency welding, mechanical push-fit arrangements, adhesives, andpins. In some configurations, the PCB 300B and the module cover 300A maycomprise apertures allowing pneumatic communication between the gasessampling passageway of the sensor module 300 and the ambient atmosphereoutside of the sensor module 300 and/or outside of the respiratorytherapy system 100. Allowing sensed gas to leak from the sensor module300 can reduce the chance of moisture build-up on the PCB 300B and canhelp to cool the PCB 300B.

In some configurations, a membrane or filter may be used to protect thesensor module 300, reduce the potential for the introduction ofcontaminants and/or pathogens into the lumen and/or gases samplingpassageway, and/or reduce the potential for delivery of contaminantsand/or pathogens to the patient. The membrane or filter may be permanentor removable and/or replaceable, and may be present in the lumen 113,present in the cuff 118, or present in the gases sampling passageway. Insome configurations, a membrane or filter can be attached to or surroundthe sensor module 300 or around one or more components of the sensormodule, including but not limited to the PCB 318 or sensor(s) 316. Themembrane or filter may be constructed from a material that can permitthe passage of water vapour while preventing the passage of liquid water(e.g. such as but not limited to stretched or expandedpolytetrafluoroethylene (PFTE) or Gore-Tex™). In some configurations,the membrane or filter may be constructed from an anti-bacterialmaterial or comprise one or more anti-bacterial compounds orcompositions, such as but not limited to silver particulates.

FIG. 4 shows a non-limiting exemplary circuit diagram 400 demonstratinga schematic for the PCB 300B. The sensor module 300 stores power in acapacitor 418 located on the PCB 300B to read and transmit data signalsfrom the one or more sensors 316. The data signals are transmitted to,for example, the controller 111 described elsewhere in this disclosurewith reference to FIG. 1, over, for example, the heating wire 114 of theconduit 112 described with reference to FIG. 1. This transmission occursby modulating the current passing through the heating wire 114 (via amodulator in the sensor module 300) to include a data packet. The datapacket is sent along the heating wire 114 to a demodulator upstream ofthe modulator. The modulator may comprise a metal-oxide-semiconductorfield-effect transistor (MOSFET)-based data shunt 416 configured toswitch on and off an added resistance to the current, optionallytransmitting data encoded in a non-return-to-zero (NRZ) fashion. In someconfigurations, the data packets generated by the modulator allow forthe generation and transmission of relatively high (1) and relativelylow (0) currents, creating a sequence of bytes representing datasignals. In some configurations, the data packets may be encoded in sucha way that allows for data and clock signals to be combined into asingle synchronized data stream, such as by the use of Biphase Mark Code(BMC, or Differential Manchester Encoding). In some configurations, aCRC error detection packet may be transmitted together with one or moreof the data packets to aid the demodulator in, for example, discardingerroneous or implausible data packets containing excess noise and/orinterference. In some configurations, the degree of modulation of thepeak current observed in the heating wire 114 is limited to 1% or about1% of the peak current.

Connected to the heating wire 114 is a diode 406 that feeds current tothe capacitor 418 of the PCB 300B. At the beginning of a pulse-widthmodulation (PWM) cycle (e.g. used to control a duty cycle of the heatingwire 114), the capacitor 418 begins to charge. To prevent the capacitor418 from overcharging, a transistor (e.g. MOSFET) power shunt 414 can beplaced along the heating wire circuit. When the voltage across thecapacitor 418 reaches a maximum allowable level (e.g. a predeterminedlevel), a microcontroller 422 of the PCB 300B switches on the powershunt 414, shorting the heating wire terminals 402, 404 such that thevoltage across the capacitor 418 stops rising. The diode 406 preventsthe charge in the capacitor 418 from flowing back into the heating wirecircuit. In some configurations, the resistance of the heating wire 114and the capacitance of the capacitor 418 are such that the rate ofincrease of voltage across the heating wire 114 is slow enough that themicrocontroller 422 has enough time to measure the voltage across thecapacitor 418 and turn on the power shunt 414 to limit excessive voltagerises across the capacitor 418.

It has been discovered that in some cases, during start-up of the PCB300B the microcontroller 422 may take a long time to warm up and runcode to measure the voltage across the capacitor 418. This time may betoo long relative to the rate of increase in voltage across the heatingwire circuit, and the risk of damage to the PCB 300B increases. In someconfigurations, then, a resistor 424 may be placed in a circuit thatconnects a V_(3V) rail (see FIG. 4) to the power shunt 414. The resistor424 helps to allocate voltage more evenly between the power shunt 414and the V_(3V) rail. As the power shunt 414 reaches a predeterminedturn-on voltage, the power shunt 414 short-circuits the heating wire 114to protect the PCB 300B. In some circumstances, with the aboveconfiguration, when the power shunt 414 is reactivated, the voltageacross a V_(s) rail may not be high enough, and a discharge resettingthe microcontroller 422 may occur. In some such configurations, themicrocontroller 422 can be programmed to turn off the power shunt 414 toallow the capacitor 418 to charge to the maximum allowable level. Afterthe capacitor 418 is charged, the power shunt 414 may be activated asdescribed above in paragraph [0030].

In some configurations, the microcontroller 422 may operate according toa software loop. The loop may be triggered by an interrupt pin (shown inFIG. 4 as the wire 410 connected to the resistor R₃ 412) of themicrocontroller 422, the interrupt pin in turn connected to the heatingwire 114 positive input HBT+. As the PWM cycle initiates, the interruptpin 410 may be triggered, which can cause the microcontroller 422 towake from a sleep state. Once awake, the microcontroller 422 may checkfor the value of the voltage across the V_(s) rail that was present atthe end of the previous PWM cycle. If the voltage was less than or equalto a minimum allowable value, a charge cycle may be initiated. If thevoltage was greater than a minimum allowable value, a data cycle may beinitiated. In the event that a charge cycle is initiated, the data shunt416 may be shut off to allow the voltage across the V_(s) rail to rise.The microcontroller 422 may continually sample the value of the voltageacross the V_(s) rail. When the microcontroller 422 determines that thevoltage across the V_(s) rail reaches a maximum allowable value, themicrocontroller 422 may turn on the power shunt 414 to prevent a furtherrise in the voltage across the V_(s) rail. In the event that a datacycle is initiated, the power shunt 414 may be turned on to preventfurther rises in the voltage across the V_(s) rail, and themicrocontroller 422 may then wait for a brief period of time to mitigatetransient background signal noise sometimes detected along the heatingwire 114. Data signals from the one or more sensors 316 may then beprepared to be transmitted using the data shunt 416. When the charge ordata cycle is complete, the microcontroller 422 receives the datasignals and transmits one or more data packets across the heating wire114 to the controller 111 based on the data signals received. Once thedata packets have been transmitted, the microcontroller 422 samples andrecords the voltage across rail V_(s) for the next iteration of the loopand monitors the PWM cycle. If the PWM is low, then the microcontroller422 enters a sleep mode to be awakened on another cycle.

FIGS. 5A and 5B describe non-limiting exemplary control algorithms 500Aand 500B that may be used together with data obtained by the sensormodule 300, assuming that the sensor module is positioned between agases conduit and a patient interface (e.g. in an ‘end-of-hose’ or EOHposition). First control algorithm 500A deals with calculation of targetEOH absolute humidity (AH) and target EOH temperature values. In 502A,the ambient temperature is measured (for example, by an ambienttemperature sensor of the respiratory therapy system 100). A gases flowrate is measured (see 502B) (for example, by using a flow rate sensorpositioned in the respiratory therapy system 100). In 504, a new(‘corrected’) ambient temperature is calculated based on a function ofthe old ambient temperature and the measured gases flow rate. In 506,the corrected ambient temperature (506A) together with one or more‘comfort settings’ representing desired parameters (including but notlimited to desired output gas temperatures and desired output gashumidity (relative or absolute)) (see 506B; obtained, for example, usingthe I/O module 110 described elsewhere in this disclosure with referenceto FIG. 1) are fed into a target generation algorithm (508). The targetgeneration algorithm determines a target EOH absolute humidity value(510A) and a target EOH temperature value (510B) based on the inputcorrected ambient temperature and the comfort settings.

The second control algorithm 500B deals with the use of the target EOHabsolute humidity value 510A and the target EOH temperature value 510Bto facilitate closed loop control of components of the respiratorytherapy system 100. With further reference to FIG. 5B, the target EOHabsolute humidity value 510A can be used in a first closed loop controlalgorithm 512A to control the temperature or duty cycle of thehumidifier heater plate 109. The target EOH absolute humidity value 510Ais compared to the actual EOH absolute humidity value 514A (determined,for example, using a sensor 316 of the sensor module 300) using acomparing module 516A. The comparing module 516A determines the percentdifference between the target and actual absolute EOH humidity values510A, 514A and feeds the difference into a closed loop control system518A (e.g. a proportional-integral-derivative or PID control system).The closed loop control system 518A adjusts the temperature or dutycycle of the humidifier heater plate 109, which in turn affects theactual EOH absolute humidity value 514A. The first closed loop controlalgorithm 512A may continually iterate to adjust the actual EOH absolutehumidity value 514A such that it approaches and maintains a value orrange of values close to the target EOH absolute humidity value 510A.

The target EOH temperature value 510B can be used in a second closedloop control algorithm 512B to control the temperature or duty cycle ofthe heating wire 114. The target EOH temperature value 510B is comparedto the actual EOH temperature value 514B (determined, for example, usinga sensor 316 of the sensor module 300) using a comparing module 516B.The comparing module 516B determines the percent difference between thetarget and actual EOH temperature values 510B, 514B and feeds thedifference into a closed loop control system 518B (e.g. aproportional-integral-derivative or PID control system). The closed loopcontrol system 518B adjusts the temperature or duty cycle of the heatingwire 114, which in turn affects the actual EOH temperature value 514B.The second closed loop control algorithm 512B may continually iterate toadjust the actual EOH temperature value 514B such that it approaches andmaintains a value or range of values close to the target EOH temperaturevalue 510B.

FIGS. 6A-6C show a non-limiting second exemplary configuration for asensing system incorporating a sensor module 600. As shown, the gasesconduit 112 (comprising heating wire 114 and gases passageway or lumen113) comprises a cuff 118. The cuff 118 comprises an outlet 119 and aslot 120. The slot 120 comprises a pair of terminal electrical contacts(not shown) linked to a portion of the heating wire 114. The sensormodule 600 can be attached to the outlet 119. The sensor module 600comprises a body 602, an inlet 604 and an outlet 606. A lumen 607extends between the inlet 604 and the outlet 606. The moduleadditionally comprises a sensing element 609. As shown in FIG. 6C, thesensing element 609 rests on a recessed area 608 of the body 602. Therecessed area 608 comprises an aperture 610 in pneumatic communicationwith the lumen 607. The sensing element 609 comprises a PCB 612comprising one or more sensors 613 positioned on a side of the PCB 612in pneumatic communication with the aperture 610. The gases passagewayextending between the lumen 607 and the one or more sensors 613 acts asa gases sampling passageway. To protect the PCB 612, the PCB 612 issandwiched between the recessed area 608 of the body 602 and a sensingelement cover 616. The sensing element cover 616 comprises a protrusion618 that fits into the slot 120 to allow for connection between thesensor module 600 and the cuff 118. Joining the protrusion 618 with theslot 120 additionally allows for electrical communication between thePCB 612 and the terminal portion of the heating wire 114.

FIGS. 7A-7I show a non-limiting third exemplary configuration for asensing system incorporating a sensor module 700. As shown in FIG. 7A,the gases conduit 112 (comprising heating wire 114 and gases passagewayor lumen 113) comprises a cuff 118. The cuff 118 comprises an outlet 119and a slot 120. The slot 120 comprises a pair of terminal electricalcontacts 123 linked to a portion of the heating wire 114. Sections ofthe inner wall of the cuff 118 comprise depressions 124. The cuff 118additionally comprises a grip section 121. The grip section 121comprises protrusions, ridges or other surface details allowing apatient or other user to handle the cuff 118. The sensor module 700comprises a body 702, an inlet 704 and an outlet 703. A lumen 707extends between the inlet 704 and the outlet 703. End portions 706 ofthe body 702 comprise recesses 708. The recesses 708 allow the endportions 706 to cantilever in a plane substantially transverse to thelumen 707. The end portions 706 additionally comprise curved ridges 710.The sensor module additionally comprises a sensing element 718. Thesensing element 718 comprises a protrusion 712 that interfaces with theslot 120, allowing for electrical communication between the terminalelectrical contact 123 and an exposed PCB contact 724 of a PCB 725positioned within the sensing element 718 (see FIG. 7I). The PCB 725comprises sensors that may receive gases via a gases sampling passagewaydefined by a second aperture 720 in communication with a first aperture717 present within the lumen 707 (see FIG. 7H). A seal 722 may bepresent between the first and second apertures 717, 720 to maintain asealed gases sampling passageway.

The sensor module 700 can be attached to the outlet 119. FIG. 7B shows asequence of cross-sections illustrating function of the end portions 706of the body 702 of the sensor module 700. When the sensor module 700 isurged against the cuff 118, the end portions 706 cantilever inwardly asthe wall of the cuff 118 defining the outlet 119 brushes against thecurved ridges 710. If the sensor module 700 is urged further against thecuff 118, the curved ridges 710 pop or snap into place in thedepressions 124 located on sections of the inner wall of the cuff 118.

The sensing element 718 module 700 comprises an input device 714. In theillustrated configuration the input device 714 comprises a depressiblemember such as a button. The input device 714 is configured or adaptedto transmit an input signal to a controller adapted to controlcomponents of the respiratory therapy system 100 (for example, thecontroller 111 described elsewhere in this disclosure with reference toFIG. 1). In some configurations, the input device 714 may comprise otherdevices, including but not limited to buttons, knobs, dials, switches,levers, touch screens, or microphones. The controller receiving theinput signal may change a number of parameters or functions dependent onthe component controlled. For example, the input signal may be used totrigger one or more of the following: turning a flow generator orhumidifier on or off, activating a pressure and/or flow ramping functionof a respiratory therapy device, increasing and/or decreasing a targethumidity level, increasing and/or decreasing a target temperature level,and activating and/or deactivating a patient wakefulness-dependentpressure response algorithm (e.g. an algorithm that modulates pressureof gases delivered by, for example, the flow generator 102 dependent ona sleep state of a patient using the respiratory therapy system 100). Insome configurations, actuating the input device in a first manner willsend a first signal to the controller 111 and actuating the input devicein a second manner will send a second signal to the controller 111. Forexample, pressing the button for a short period of time may cause thepressure of gases delivered by the flow generator 102 to decrease, anddepressing the button for a prolonged period of time may cause the flowgenerator 102 to be turned off. In some configurations, input signalsfrom the input device 714 may be transmitted to the heating wire 114 bysuperimposing an input signal over the heating wire 114. Thesuperimposition of the input signals may be similar to thesuperimposition of the data signal described elsewhere in thisdisclosure. In other configurations, the input signal may be transmittedto components of the respiratory therapy system 100 wirelessly, e.g.using RFID or wireless communications technologies including but notlimited to Wi-Fi, Bluetooth, 2G, 3G, or 4G.

The sensor module 700 additionally comprises an output device 716. Inthe illustrated configuration the output device 716 comprises alight-emitting display (LED). In other configurations, the output device716 may comprise, for example, displays, speakers, or vibrating/tactileoutput elements. In some configurations, the output device 716communicates with a microcontroller 732 attached to the PCB 725. In someconfigurations, the microcontroller 732 is configured to receive datasignals from one or more of the components of a respiratory therapysystem to which the sensor module 700 is attached. Data signals receivedmay be transmitted to the microcontroller 732 (using, for example, theheating wire 114 as described elsewhere in this disclosure, or throughRFID or wireless communications technologies including but not limitedto Wi-Fi, Bluetooth, 2G, 3G, or 4G). The microcontroller 732 maycommunicate with the output device 716 to inform the patient or userabout operating conditions or parameters of the components of therespiratory therapy system 100. In some configurations, the outputdevice 716 may alert or warn the patient of leaks or fault conditions.For example, the LED of the output device 716 may flash if a significantgas leak is determined at one of the components, or if a fault conditionof one of the components is determined. In some configurations, the LEDmay blink for a predetermined period of time during therapy, e.g. duringthe first 5 seconds of therapy, to reassure the user that the sensormodule 700 is operational.

Unless the context clearly requires otherwise, throughout thedescription and the claims, the words “comprise”, “comprising”, and thelike, are to be construed in an inclusive sense as opposed to anexclusive or exhaustive sense, that is to say, in the sense of“including, but not limited to.”

Where, in the foregoing description reference has been made to integersor components having known equivalents thereof, those integers orcomponents are herein incorporated as if individually set forth.

The disclosed methods, apparatus and systems may also be said broadly tocomprise the parts, elements and features referred to or indicated inthe disclosure, individually or collectively, in any or all combinationsof two or more of said parts, elements or features.

Reference to any prior art in this specification is not, and should notbe taken as, an acknowledgement or any form of suggestion that thatprior art forms part of the common general knowledge in the field ofendeavour in any country in the world.

Although the present disclosure has been described in terms of certainembodiments, other embodiments apparent to those of ordinary skill inthe art also are within the scope of this disclosure. Thus, variouschanges and modifications may be made without departing from the spiritand scope of the disclosure. For instance, various components may berepositioned as desired. Moreover, not all of the features, aspects andadvantages are necessarily required to practice the present disclosure.Accordingly, the scope of the present disclosure is intended to bedefined only by the claims that follow.

What is claimed is:
 1. A sensor module adapted to be positioned betweencomponents of a respiratory therapy system, the sensor modulecomprising: a gases inlet; a gases outlet; a lumen extending between thegases inlet and the gases outlet; one or more sensors adapted todetermine one or more characteristics of gases passing through thelumen; and an input device adapted to transmit an input signal to atleast one of the components of the respiratory therapy system.
 2. Thesensor module of claim 1, wherein the sensor module is adapted to bepositioned between a gases conduit and a patient interface.
 3. Thesensor module of claim 2, wherein the sensor module is configured toelectrically interface with a heating wire positioned in, on, around ornear the gases conduit.
 4. The sensor module of claim 3, wherein thesensor module is adapted to transmit a data signal from the one or moresensors to the at least one component by superimposing the data signalover a power signal of the heating wire.
 5. The sensor module of claim3, wherein the sensor module is adapted to transmit an input signal fromthe input device to the at least one component by superimposing theinput signal over a power signal of the heating wire.
 6. The sensormodule of claim 1, wherein the input device comprises a depressiblemember, and wherein the sensor module is configured to transmit a firstinput signal when the depressible member is actuated in a first mannerand to transmit a second input signal when the depressible member isactuated in a second manner.
 7. The sensor module of claim 1, furthercomprising an output device adapted to receive an output signal from atleast one of the components of the respiratory therapy system andcommunicate the output signal to a user.
 8. The sensor module of claim7, wherein the output device comprises an alarm that actuates uponreceiving an output signal indicating a disconnection, fault condition,attachment or removal of one or more of the components of therespiratory therapy system.
 9. The sensor module of claim 1, wherein atleast one of the one or more sensors is positioned in a gases samplingpassageway present outside of but in pneumatic communication with thelumen.
 10. The sensor module of claim 9, further comprising an apertureallowing for communication between the gases sampling passageway andambient air outside of the respiratory therapy system.
 11. The sensormodule of claim 1, wherein one or more of the sensors comprise amembrane that allows for the passage of water vapour without allowingfor the passage of liquid water.
 12. A sensor module adapted to bepositioned between components of a respiratory therapy system, thesensor module comprising: a gases inlet; a gases outlet; a lumenextending between the gases inlet and the gases outlet; one or moresensors adapted to determine one or more characteristics of gasespassing through the lumen; and a controller adapted to transmit a signalto at least one of the components of the respiratory therapy system, thesignal being a function of a data signal received from at least one ofthe one or more sensors.
 13. The sensor module of claim 12, wherein thecontroller is adapted to receive a data signal from a sensor incommunication with a component of the respiratory therapy system andtransmit an output signal to the component, the output signal being afunction of the data signal received.
 14. The sensor module of claim 12,wherein the controller transmits a fault signal to at least one of thecomponents of the respiratory therapy system if an implausible datasignal is obtained at one or more of the sensors.
 15. A sensor moduleadapted to be fitted on a conduit positioned between components of arespiratory therapy system, the sensor module comprising: a gasessampling passageway adapted to receive gases from a lumen of theconduit; one or more sensors adapted to determine one or morecharacteristics of gases located within the gases sampling passageway;and a data transmission element adapted to transmit a data signaloutputted by the one or more sensors to at least one of the componentsof the respiratory therapy system.
 16. The sensor module of claim 15,wherein the gases sampling passageway extends in a directionsubstantially perpendicular to the lumen.
 17. The sensor module of claim15, wherein the conduit comprises a heating wire, and wherein the datatransmission element is configured to transmit the data signal bysuperimposing the data signal over a power signal of the heating wire.18. The sensor module of claim 15, further comprising an apertureallowing for communication between the gases sampling passageway andambient air outside of the respiratory therapy system.
 19. The sensormodule of claim 15, further comprising an input device adapted totransmit an input signal to at least one of the components of therespiratory system.
 20. The sensor module of claim 15, wherein one ormore of the sensors comprise a membrane that allows for the passage ofwater vapour without allowing for the passage of liquid water.